A Global Perspective Why Population Aging Matters

Aging of population (also known as demographic aging, and population aging) is a summary term for shifts in the age distribution (i.e., age structure) of a population toward older ages. A direct consequence of the ongoing global fertility transition (decline) and of mortality decline at older ages, population aging is expected to be among the most prominent global demographic trends of the 21st century. Population aging is progressing rapidly in many industrialized countries, but those developing countries whose fertility declines began relatively early also are experiencing rapid increases in their proportion of elderly people. This pattern is expected to continue over the next few decades, eventually affecting the entire world. Population aging has many important socio-economic and health consequences, including the increase in the old-age dependency ratio. It presents challenges for public health (concerns over possible bankruptcy of Medicare and related programs) as well as for economic development (shrinking and aging of labor force, possible bankruptcy of social security systems). Defining and measuring population aging
As the study of population aging is often driven by a concern over its burdening of retirement systems, the aging of population is often measured by increases in the percentage of elderly people of retirement ages. The definition of retirement ages may vary but a typical cutoff is 65 years, and nowadays a society is considered relatively old when the fraction of the population aged 65 and over exceeds 8-10%. By this standard, the percentage of elderly people in the United States stood at 12.6% in 2000, compared with only 4.1% in 1900 and a projected increase to 20% by the year 2030. A related measure of population aging is the elderly dependency ratio (EDR): the number of individuals of retirement ages compared to the number of those of working ages. For convenience, working ages may be assumed to start at age 15, although increasing proportions of individuals pursue their education beyond that age and remain, meanwhile, financially dependent, either on the state or, increasingly, on their parents or bank managers. The ratio of the elderly dependent population to the economically active (working) population is also known as old-age dependency ratio, age-dependency ratio or elderly dependency burden and is used to assess intergenerational transfers, taxation policies, and saving behavior. Another indicator of the age structure is the aging index (sometimes referred to as the elder-child ratio), defined as the number of people aged 65 and over per 100 youths under age 15. In 2000, only a few countries (Germany, Greece, Italy, Bulgaria, and Japan) had more elderly than youth (aging index above 100). By 2030, however, the aging index is projected to exceed 100 in all developed countries, and the index of several European countries and Japan are even expected to exceed 200. To date, aging indexes are much lower in developing countries than in the developed world, but the proportional rise in the aging index in developing countries is expected to be greater than in developed countries. These indicators of population aging are mere head-count ratios (HCR), that is, they simply relate the number of individuals in large age categories. These indicators fail to take into account the age distribution within these large categories, in particular among the elderly. When the fertility and mortality trends responsible for population aging have been fairly regular over time, the population growth is positively correlated with age (i.e., the oldest age groups are growing fastest). This implies that if the proportion of the population over age 65 is increasing, within that 65-and-over population the proportion over, say, age 80 is also increasing. As health, financial situation, and consumption patterns may vary greatly between 65 year-olds and 80 year-olds, simple ratios conceal important heterogeneity in the elderly population. Increasingly, attention is paid to the "oldest olds" (typically age 80 and over). A long-time subject of curiosity, the number of centenarians is growing even faster. Estimated at 180,000 worldwide in 2000, it could reach 1 million by 2030 (United Nations 2001). The second class of indicators for population aging is the group of statistical measures of location (median, mean and modal ages of population). The median age -- the age at which exactly half the population is older and another half is younger -- is perhaps the most widely used indicator. For the year 2000, the median age in the United States was 36 years, a typical age for most developed countries and twice the median age for Africa (United Nations 2001). Because it is more sensitive to changes at the right-hand tail of the age distribution (i.e., the oldest old ages), the mean age of population might in fact be preferred to the median age to study the dynamics of population aging. Since population aging refers to changes in the entire age distribution, any single indicator might appear insufficient to measure it. The age distribution of population is often very irregular, reflecting the scars of the past events (wars, depression etc.), and it cannot be described just by one number without significant loss of information. Were the age distribution to change in a very irregular fashion over the age range, for instance, much information would be lost by a single-index summary. Therefore, perhaps the most adequate approach to study population aging is to explore the age distribution through a set of percentiles, or graphically by analyzing the population pyramids. Demographers commonly use population pyramids to describe both age and sex distributions of populations. Youthful populations are represented by pyramids with a broad base of young children and a narrow apex of older people, while older populations are characterized by more uniform numbers of people in the age categories. Very Young Populations Contribute to Strife, Study Concludes Iraq, Afghanistan, Sudan and Congo have all suffered horrors brought on by disastrous governance and violent conflict. But they, and many of Africa’s poorest countries, have something else in common: very young populations. Skip to next paragraphWhile it is not clear exactly how the age of a population contributes to strife, research by Population Action International suggests that it is no simple coincidence that 80 percent of the civil conflicts that broke out in the 1970s, ’80s and ’90s occurred in countries where at least 60 percent of the population was under 30, and that almost 9 of 10 such youthful countries had autocratic rulers or weak democracies. In poor countries with rapidly growing populations, intense competition for education, jobs and land among the young contributes to discontent and makes it easier for rebel groups to recruit, said Elizabeth Leahy, the primary author of a new report for Population Action, a nonprofit group in Washington. William L. Nash, a retired Army major general who now directs Center for Preventive Action of the Council on Foreign Relations, said: “You’ve got a lot of young men. You’ve got a lot of poverty. You’ve got a lot of bad governance, and often you’ve got greed with extractive industries. You put all that together, and you’ve got the makings of trouble.” One strategy is to reduce the birthrates and the mortality rates of infants and younger children, according to Population Action, which hopes its research will improve contraception programs, education for girls and health services for children and pregnant women. “The budget realities are such that unless you can show how your programs help achieve larger ends — security, development, poverty reduction, democracy — traditional rationales for humanitarian assistance aren’t enough,” said Tod J. Preston, a senior adviser at the group. In a December 2005 report titled “More Than Humanitarianism,” a Council on Foreign Relations task force with bipartisan leadership called population a neglected area of American policy, one that could help lower the odds of conflict. Population Action’s report, “The Shape of Things to Come,” features Nigeria, Africa’s most populous country with 132 million people and a major supplier of oil to the United States, as an example of the strategic risks posed by youthful, volatile nations plagued by corruption, instability and poverty. Rebels there, enraged by the distribution of oil revenues, have attacked the industry, which is important to rich nations. In Nigeria, almost three quarters of the population is under 30. Birthrates are very high, at more than five children per woman. Less than half the women have attended school and fewer than one in 10 use modern contraception. A fifth of children die before they turn 5 — a factor specialists say encourages couples to have more children to ensure that some survive. Almost a billion people live in countries where birthrates average at least four children per woman, among them, Nigeria, Afghanistan, Iraq, Pakistan, Somalia and Sudan. Those countries need help to improve infant and child survival and the educational status of women, to reduce population pressures and to become more stable, the report says. If nothing changes, the authors say, the populations of such countries will double in 35 years. Advocates at Population Action are critical of deep cuts in international family planning programs in the Bush administration’s 2008 budget proposal, but a Democratic-controlled Congress is likely to reverse them, as the Republican-controlled Congress did last year. The advocates acknowledged that the administration’s efforts to increase financing of programs to combat AIDS and malaria are likely to help prevent the deaths of many children — another goal. The group’s researchers found that some countries that have aggressively pursued family planning programs have significantly changed their age structures in a relatively brief span of 25 years. The report cites Iran as an example. Since the 1990s, Iran has made modern contraceptives available free at public clinics. Births are down to two children per woman, from six and a half at the time of the 1979 revolution. Lt. Gen. Claudia J. Kennedy, who is a member of the Population Action board and was in charge of Army intelligence when she retired in 2000, said the United States needed to focus more on efforts to improve the status of women and ease population pressures in developing countries. “When people think reproductive issues are girlie because it involves a woman’s biology, they ignore the social, political and economic impact of not paying attention to these matters,” she said. “And it reflects a pervasive attitude that if it’s about women, it’s unimportant, but if it’s about what huge weapons system to buy, that’s more manly and more important.”